As the son of a famous pianist who spent much of his youth touring the world’s cultural capitals, Shinichi Chiaki has grown up to be a talented violinist and pianist in his own right. More than anything else, however, Chiaki wants to be a conductor. Yet, after being rebuffed by the world-renowned conductor Sebastiano Vieira, he desultorily heads for Japan’s Momogaoka Music Academy to pursue his piano studies. But no matter how hard he tries, Chiaki cannot keep his desire to conduct in check. As a result, when his frustration boils over, he and his teacher, Kouzou Etoh, angrily part ways, leaving the young pianist to pursue his passion. After refusing to apologize to Etoh, Chiaki is poised to start looking for a new career when he is struck by the playing of Megumi “Nodame” Noda, an extraordinarily passionate but undisciplined pianist who also happens to be his neighbor. Though Nodame quickly takes a liking to him, Chiaki resists getting involved. He’s repulsed by her poor hygiene and unbelievably messy apartment, but eventually agrees to be Nodame’s new piano tutor. As Chiaki rediscovers his own love for the piano and struggles to rein in his student’s playing, he’s stunned to find that Nodame has fallen madly in love with him.

Although he should be concentrating on his upcoming exams, second-year violin major Ryutarou Mine can’t keep his mind from wandering to his band’s upcoming performance at the Momogaoka Music Academy’s school festival. Having already parted ways with his no-nonsense accompanist, Chiaki, Mine is desperate to find someone to help him prepare for his exams – and then he meets Nodame. After agreeing to help, Nodame asks Chiaki to help her learn the violin sonata that Mine is playing for his exam. But when he spots them together at the local restaurant owned by Mine’s father, Chiaki wishes them luck with the difficult piece and storms off. And after seeing Chiaki walking arm-in-arm with his ex-girlfriend leaves Nodame despondent and unable to play, it’s up to Mine to reunite her with the object of her affection. While Mine doubts that he has any chance of success, his confidence in his matchmaking skills gets a boost after learning that Chiaki has been cooking for Nodame. When Mine tries counseling Nodame on her wardrobe, hair and makeup, he’s stunned to discover just how little she knows about using her womanly charms to woo Chiaki. Yet, after Mine blames him for rendering Nodame unfit as an accompanist, Chiaki offers to help them prepare for the upcoming violin exam. Though Mine balks at first, he and Nodame soon find themselves listening carefully to what Chiaki has to say about the Beethoven. However, when Nodame falls ill on the eve of the exam, Chiaki agrees to fill in for her and accompany Mine just this once. And though Mine proves to be just as undisciplined as Nodame, Chiaki relies on his own considerable talents to pull him through the exam.

Though frustrated with his studies and longing to return home to Yamagata, timpani student Masumi Okuyama has a change of heart after one look at the handsome and talented Chiaki. But once he spots Nodame following Chiaki, Masumi is left smoldering with jealousy and looking for way to come between her and his new crush. And as Chiaki makes it clear that he’s not interested in being her boyfriend, Nodame continues her pursuit even as she finds herself the target of ominous threats and pranks masterminded by Masumi.

With Mine’s help, Nodame lays a trap that exposes Masumi as her tormentor. Revealing that he is behind the pranks, Masumi admits that his infatuation with Chiaki has led him to try to force Nodame out of the picture. In a desperate effort to win Chiaki’s affection and respect, Masumi challenges Nodame to see which one of them can secure a date with the aspiring conductor on Christmas Eve. Now the only thing Masumi has to do is to befriend him. Meanwhile, after unwittingly accepting an invitation to Christmas Eve dinner with Nodame, Chiaki becomes despondent over news that a rival student has been chosen to attend a prestigious conducting seminar in Germany.

As Chiaki learns that Nodame is planning to have him over for dinner on December 24th, Mine decides to give Masumi’s chances a boost by inviting Chiaki to a rehearsal of the school’s A Orchestra. However, upon seeing Chiaki in the audience, Masumi’s exuberance gets the best of him, and he ends up making a fool of himself and Mine. Finally, now that both he and Nodame have lost out on their bids to land a date on Christmas Eve, Masumi vows to return home to Yamagata. But when a Christmas Eve invitation from Saiko jogs his memory, Chiaki remembers being asked to dinner by Nodame. And after finding her rehearsing one of his compositions with Masumi and Mine, Chiaki joins them for a Christmas Eve quartet.

As Chiaki resolves to take control of his own destiny and pursue his dream of being a conductor, the students at Momogaoka Music Academy are abuzz with news of a strange foreigner who’s been seen lurking in the school’s hallways and classrooms. As speculation about his identity grows, the stranger approaches Nodame and, identifying himself as a mild-mannered German tourist named Milch Holstein, asks her to dinner to help pass the time before he is supposed to meet a friend the following day. But instead of taking him to a restaurant, Nodame brings Milch to Chiaki’s apartment. Suspecting that Milch’s intentions are less than honorable, Chiaki surprises Nodame with an invitation to spend the night, if only to make sure that she doesn’t accompany the lecherous stranger back to his hotel.

As Chiaki contemplates making an official move into the conducting program, Mine excitedly announces that Franz von Stresemann, one of Europe’s most prominent conductors, has arrived to teach at the school. However, when he finally gets a look at the man who might become his new mentor, Chiaki is stunned to discover that von Stresemann is none other than Milch, the same man he suspects of pursuing Nodame. And after assembling a new orchestra made up of eccentric students like Mine and Masumi, Milch invites Nodame to be the group’s mascot.

Despite being troubled by Milch’s attentions to Nodame, Chiaki decides to change his major in order to study under the world-renowned maestro. Refusing to approve of the change, Milch reveals that his decision is rooted in Chiaki’s admiration for his longtime professional and personal rival, Sebastiano Vieira. However, Nodame is determined to help Chiaki realize his dream and, following the new orchestra’s strange first meeting with their conductor, she tearfully pleads with Milch to reconsider. Finally, as Chiaki is about to submit his resignation from the school to pursue his dream elsewhere, Milch agrees to allow the transfer, but only if Nodame kisses him first.

As questions about his identity and intentions swirl about the student body, newly hired conductor Milch Holstein (aka Franz von Stresemann) calls the first rehearsal of an orchestra made up of the school’s misfits and outcasts. However, after he is knocked unconscious while trying to kiss Nodame, Milch is in no shape to conduct. Facing a mutiny by the disgruntled players, Nodame persuades everyone to rehearse under Chiaki who, despite his reservations, accepts the challenge. Unfortunately, he finds the orchestra woefully unprepared with Mine as their concertmaster. And after helping Milch into the rehearsal hall, Nodame is certain that one look at Chiaki’s leadership will convince the groggy maestro to allow him into the conducting program.

Though Chiaki is doubtful that this ragged band of misfits could ever become a talented orchestra, he resolves to make the most of the opportunity and patiently forges ahead with the rehearsal. But their sloppy musicianship and disrespect finally get the best of him, and Chiaki concludes that they are hopeless. After seeing him give up, Milch takes to the podium and denounces Chiaki as a failure.

Adopting a very different approach than Chiaki, Milch implores Mine and the others to stop worrying about minor technical details and have fun with the music. Once they have relaxed, Chiaki watches in amazement as Milch makes the S Orchestra come alive in their playing. Although he still refuses to sign the transfer, Milch tells Chiaki that if he will continue his piano studies, he can be his assistant in leading the S Orchestra.

With just one month to prepare for the S Orchestra’s face-off against Momogaoka Music Academy’s A Orchestra, Milch takes everyone by surprise by officially naming Chiaki as his deputy conductor. Just minutes after the big announcement, however, Milch promptly heads off to a date with an escort and leaves the rehearsal in Chiaki’s hands. After proving himself a capable conductor and musician, Chiaki is befuddled when he finds the orchestra members turning to him for advice on everything from cooking to careers. But when Nodame shows up on his doorstep with Sakura Saku, a contrabassist whose family’s financial troubles have left her in danger of having to drop out of school, Chiaki has little patience for her problems.

True to form, Milch fails to show up at the S Orchestra’s next rehearsal, leaving the conducting duties to his deputy, Chiaki. When Sakura also fails to show, Nodame persuades Chiaki to give her another chance to continue in the orchestra. While expecting to find the Sakuras living in poverty, Nodame and Chiaki are surprised to discover that, though he is suffering from a business downturn, the father has a valuable collection of rare violins that he finally agrees to sell to finance his daughter’s education.

Two weeks before their concert debut, Milch continues to miss rehearsals, forcing Chiaki to keep filling in for him. Frustrated at their lack of discipline, and especially Mine’s highly theatrical playing, Chiaki tracks down his mentor at the One More Kiss Club, where he finds Nodame in the hands of the sexy hostesses, who are teaching her how to impress him! Back on campus, Milch then pledges to devote his attention to the A Orchestra and crush Chiaki and his group in their upcoming showdown. Though Chiaki is resigned to disbanding the group, the ragtag orchestra members vow to demolish the A Orchestra with him as their leader. And upon realizing that he’s been presented with a great opportunity, Chiaki looks to Beethoven for inspiration and rededicates himself to preparing for the challenge.